Printing plate and method for fabricating the same

ABSTRACT

A printing plate and method for fabricating the same is disclosed. A metal layer is first formed on a glass substrate. The metal layer is then patterned in a predetermined shape. The glass substrate is next etched to a predetermined depth using the patterned metal layer as a mask and the metal layer removed. If necessary, additional metal layers have the same or different patterns may be formed on the glass substrate and the glass substrate etched after each metal layer is formed thereon until a desired etching depth in the glass is achieved.

This application claims the benefit of Korean Patent Application No.P2004-89311, filed on Nov. 4, 2004, which is hereby incorporated byreference as if fully set forth herein.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a printing method for forming apattern, and more particularly, to a printing plate and a method forfabricating the same, to print a printing material of the predeterminedpattern on a printing roll.

BACKGROUND

Generally, an LCD device and a semiconductor device are formed withrepeated steps of depositing a plurality of layers and etching thecoated layers. To deposit each of the layers, a deposition process suchas CVD (Chemical Vapor Deposition) and sputtering is performed.Photolithography is also performed to etch the coated layers.

If the deposition and etching processes are complicated due to theformation of the plurality of layers, the productivity is lowered. Thus,it is desirable to provide simplified deposition and etching processesfor mass production.

In comparison with forming the desired pattern by coating the pluralityof layers using CVD and sputtering and patterning the coated layersusing photolithography, forming the desired pattern by printing issimpler and easier.

In the process of forming the desired pattern by printing, after thepredetermined material is printed on a printing roll from a printingplate, the printed material of the printing roll is re-printed on asurface of a substrate by rolling the printing roll on the substrate,thereby forming the desired pattern on the substrate. In this case,physical contact is generated between the substrate and the printingroll, causing various problems with the substrate and the printing roll.However, as the printing method is advantageous for mass production, ithas been developed with the various modifications.

Hereinafter, a printing method and a printing plate according to therelated art will described with reference to the accompanying drawings.

FIGS. 1A to 1D are cross sectional views of the printing methodaccording to the related art.

As shown in FIG. 1A, a printing plate is prepared having an organicmaterial 20 patterned in the predetermined shape on a glass substrate10.

Referring to FIG. 1B, a printing material 30 is coated on the printingplate.

As shown in FIG. 1C, a printing roller 40 having a coating 45 adheredthereto rolls on the printing plate, whereby the printing material 30 isprinted on the coating 45.

As shown in FIG. 1D, the printing roller 40 having the printing material30 rolls on a substrate 60. Thus, the printing material 30 is printed onthe substrate 60, whereby the printing material 30 of the predeterminedpattern is formed on the substrate 60.

At this time, a printing plate on which the organic material 20 of thepredetermined pattern is formed on the glass substrate 10 will bedescribed in detail.

FIGS. 2A to 2E are cross sectional views of the process for fabricatingthe printing plate according to the related art.

First, as shown in FIG. 2A, the organic material 20, a metal layer 25and a photoresist 35 are sequentially coated on the entire surface ofthe glass substrate 10.

Referring to FIG. 2B, the photoresist 35 is patterned in thepredetermined shape by photolithography.

As shown in FIG. 2C, the metal layer 25 is etched using the patternedphotoresist 35 as a mask.

As shown in FIG. 2D, the organic material 20 is etched using thepatterned photoresist 35 and metal layer 25 as a mask.

After that, as shown in FIG. 2E, the organic material 20 is formed inthe predetermined pattern on the glass substrate 10 by removing thepatterned photoresist 35 and metal layer 25, thereby completing theprinting plate.

In the related art printing plate, the organic material 20 is formed inthe predetermined pattern on the glass substrate 10.

However, the printing method and the printing plate according to therelated art have the following disadvantages.

First, as shown in FIG. 1C, the printing roller 40 having the coating 45adhered thereto rolls on the printing plate, so the printing material 30coated on the printing plate is printed on the coating 45. In this case,the coating 45 is also generally formed of an organic material.Accordingly, the printing material 30 is printed between the organicmaterials. However, the printing material 30 may not be completelyprinted on the coating 45 from the organic material 20 of the printingplate. Thus, it may not be possible to form a minute pattern.

As shown in FIG. 2D, when etching the organic material 20 using thepatterned photoresist 35 and metal layer 25 as a mask, end portions ofthe organic material 20 may not be etched in the desired pattern, so itmay again not be possible to form a minute pattern sufficient to be usedin semiconductor and/or LCD fabrication.

SUMMARY

By way of introduction only, a printing plate includes a glass substrateand a plurality of grooves in the glass substrate forming a surface witha predetermined shape. A portion of the surface in which the grooves arenot formed have dimensions sufficient to accept a printing materialcapable of being used in fabrication of at least one of a semiconductordevice or an LCD device.

In another aspect, a method for fabricating a printing plate includesforming a metal layer on a glass substrate; patterning the metal layerin a predetermined shape; and etching the glass substrate to apredetermined depth using the patterned metal layer as a mask.

In the printing method according to the present invention, instead ofusing the organic material for formation of the pattern, patterning thepattern uses the glass substrate itself, so that it is possible to forma minute pattern.

To pattern the glass substrate, the glass substrate is etched using thepatterned metal layer as a mask. The etching method is a dry-etchingmethod and/or a wet-etching method.

Using a wet-etching method, the glass substrate is etched in bothhorizontal and vertical directions. Accordingly, even though the glasssubstrate is etched using the metal layer as a mask, it is difficult atbest to form a minute pattern. Using a dry-etching method, the glasssubstrate is not etched in the horizontal direction. Thus, if the glasssubstrate is etched using the metal layer as a mask by the dry-etchingmethod, it is easier to form a minute pattern. In this respect, it ispreferable to etch the glass substrate using the dry-etching method.

Using the dry-etching method, the metal layer as well as the glasssubstrate is etched. However, the etching rate of the metal layer issmaller than the etching rate of the glass substrate. Thus, the glasssubstrate is etched to a greater depth than the metal layer when etchingboth simultaneously.

Accordingly, in due consideration of the thickness of the metal layerand the etching depth of the glass substrate, etching the glasssubstrate using the metal layer as a mask may be performed repetitively,thereby etching the glass substrate to the desirable depth.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIGS. 1A to 1D are cross sectional views of the process for a printingmethod according to the related art;

FIGS. 2A to 2E are cross sectional views of the process for fabricatinga printing plate according to the related art;

FIGS. 3A to 3H are cross sectional views of the process for fabricatinga printing plate according to the preferred embodiment of the presentinvention; and

FIGS. 4A to 4D are cross sectional views of the process for forming apattern of a metal layer on a glass substrate according to the preferredembodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Hereinafter, a printing method and a printing plate according to thepresent invention will be described with reference to the accompanyingdrawings.

FIGS. 3A to 3H are cross sectional views of the process for fabricatinga printing plate according to one embodiment of the present invention.FIGS. 4A to 4D are cross sectional views of the process for forming apattern of a metal layer on a glass substrate according to oneembodiment of the present invention.

As shown in FIG. 3A, a first metal layer 200 is formed on an entiresurface of a glass substrate 100 having first portions (to be etched)102 and second portions (not to be etched) 104.

Referring to FIG. 3B, the first metal layer 200 is patterned in thepredetermined shape such that the first metal layer 200 remains on thesecond portions 104 of the substrate 200.

The preferable method for patterning the first metal layer 200 will bedescribed with reference to FIGS. 4A to 4D.

First, as shown in FIG. 4A, a photoresist 300 is formed on the metallayer 200 of the glass substrate 100.

As shown in FIG. 4B, the photoresist 300 is patterned in thepredetermined shape by photolithography, which uses light irradiationand development.

As shown in FIG. 4C, the metal layer 200 is next etched using thepatterned photoresist 300 as a mask. The metal layer 200 is etched usingdry-etching or wet-etching.

As shown in FIG. 4D, the patterned photoresist 300 is then removed.

The metal layer 200 is patterned on the glass substrate 100 according tothe process of FIGS. 4A to 4D.

After that, as shown in FIG. 3C, the glass substrate 100 is etched to apredetermined depth using the patterned metal layer 200 as a mask. Asshown, the glass substrate 100 is dry-etched.

As shown in FIG. 3D, the patterned first metal layer 200 is thenremoved, thereby fabricating the printing plate having the glasssubstrate 100 of the first pattern.

At this time, the etching depth of the glass substrate 100 depends onthe thickness of the first metal layer 200. In more detail, when theglass substrate 100 is etched, the first metal layer 200 is also etched.However, the etching ratio to the first metal layer 200 is lower thanthe etching ratio to the glass substrate 100. For example, when dryetching, the etching rate of the metal layer 200 is about 200 Å/minute,and the etching rate of the glass substrate 100 is about 800 Å/minute to2000 Å/minute. Thus, the etching ratio of the metal layer 200 to theglass substrate 100 is about 1:4 to about 1:10.

Thus, so long as the glass substrate 100 is etched below a predeterminedamount or etching occurs for less than a predetermined time, the etchingprocess will be completed before completely etching the first metallayer 200. For example, if the etching rate of the first metal layer 200is about 200 Å/minute, the etching rate of the glass substrate 100 isabout 2000 Å/minute, the first metal layer 200 is 2000 Å thick, andetching may be performed for a maximum of 10 minutes, and thus theetching depth of the glass substrate 100 is about 20,000 Å (2 μm) atmaximum. Accordingly, if the desired depth for etching the glasssubstrate 100 is below 2 μm, it is possible to form the printing platewith one process of FIGS. 3A to 3D. However, if the desired depth foretching the glass substrate 100 is above 2 μm, it is necessary to repeatthe aforementioned process several times if it is not desirable toincrease the thickness of the metal layer 200.

Alternately, if the thickness of the metal layer 200 is increased, thenthe etching depth of the glass substrate 100 may also be increasedwithout increasing the number of process steps. However, it may bedifficult to pattern a thick metal layer 200. Accordingly, there may bea limit to the amount by which the thickness of the first metal layer200 may be increased. This correspondingly limits the increase ofetching depth of the glass substrate 100.

As previously indicated, if the desired etching depth of the glasssubstrate 100 having the first pattern in FIG. 3D is not obtained, andthe thickness of the metal layer 200 cannot be increased, additionalrepetitive processes are performed as follows.

As shown in FIG. 3E, a second metal layer 200 a is formed on the glasssubstrate 100.

As shown in FIG. 3F, the second metal layer 200 a is patterned. At thistime, as shown in FIG. 3F(1), the pattern of the second metal layer 200a may be same as the pattern of FIG. 3B. In other words, the secondmetal layer 200 a may be patterned such that the second metal layer 200a remains only on the second portions 204.

Alternatively, as shown in FIG. 3F(2), the pattern of the second metallayer 200 a may be different from the pattern of FIG. 3B. As shown inFIG. 3F(2), the second metal layer 200 a is patterned such that thesecond metal layer 200 a remains on the second portions 204 and at leastone of first portions 202 a. Alternatively, the first portion 202 a onwhich the second metal layer 200 a is formed has a narrower width thanthat of the other first portions 202.

Preferably, the second metal layer 200 a is patterned according to theprocess of FIGS. 4A to 4D.

After that, as shown in FIG. 3G, the glass substrate 100 is etched usingthe second metal layer 200 a as a mask. As shown above, the glasssubstrate 100 may be dry etched.

In the process for patterning the second metal layer 200 a, if thepattern of the second metal layer 200 a is the same as the pattern ofFIG. 3B, the etching depth is uniform, as shown in FIG. 3G(1).Alternatively, if the pattern of the second metal layer 200 a isdifferent from the pattern of FIG. 3B, the etching depth is not uniform,as shown in FIG. 3G(2).

As shown in FIG. 3H, the patterned second metal layer 200 a is thenremoved, thereby fabricating the printing plate having the glasssubstrate 100 of the second pattern. The result may be a glass substratehaving grooves 110 with a uniform etching depth, as shown in FIG. 3H(1),or a glass substrate having grooves 120, 122 with a nonuniform etchingdepth, as shown in FIG. 3H(2).

The process for etching the glass substrate 100 using the second metallayer 200 a as a mask is repetitively performed, making it possible toetch the glass substrate 100 to a desired depth. In the drawings, theaforementioned process is repeated once. However, if necessary, it ispossible to repeat the aforementioned process several times. If thesecond metal layer 200 a is thin, the number times the process isrepeated increases. In this respect, it is preferable to form the thickmetal layer. As described above, however, as the metal layer increasesin thickness, the difficultly in patterning the metal layer alsoincreases. Accordingly, it is preferable to form a metal layer having athickness within the scope suitable for the patterning process.

The at least one of grooves having the narrower width than that of theother grooves has a shallower depth than that of the other grooves. Onother words, at least one of grooves having a wider width than that ofthe other grooves has deeper depth than that of the other grooves.

In the printing method according to the present invention, instead ofusing the organic material for formation of the pattern, the process ofpatterning the pattern uses the glass substrate itself. It is thuspossible to prevent inaccurate patterns from being formed.

In addition, if the metal layer is not thick enough to permit etching ofthe glass substrate to the desired depth, repetitive etching steps maybe performed. Thus, even though the metal layer is etched, it ispossible to etch the glass substrate to the desired depth.

If performing repetitive etching steps, it is possible to form variousmask shapes by applying various patterning methods to the metal layerfor the mask.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A method for fabricating a printing plate with a plurality ofgrooves, the method comprising: forming a first metal layer on a glasssubstrate including a first region and a second region apart from thefirst region; patterning the first metal layer in a predetermined shape;dry etching the glass substrate to a first depth using a patterned firstmetal layer as a first etch mask; removing the patterned first metallayer, thereby performing one cycle; forming a second metal layer on theetched glass substrate; patterning the second metal layer in the samearea as the patterned first metal layer; dry etching the etched glasssubstrate to a second depth using a patterned second metal layer as asecond etch mask identical to the first etch mask, wherein the first andsecond depth are formed within the same region; wherein the first andsecond metal layers are etched when the glass substrate is etched, anetching rate of the first and the second metal layer is lower than theetching rate of the glass substrate and the etching ratio of the firstand the second metal layer to the glass substrate is about 1:4 to about1:10; and wherein a number of repetitions of the one cycle depends on athickness of the first metal layer and an etching depth of the glasssubstrate.
 2. The method of claim 1, wherein the predetermined shape ofthe patterned first metal layer is the same as the patterned secondmetal layer.
 3. The method of claim 1, wherein the predetermined shapeof the metal patterned first layer is different from that of thepatterned second metal layer.
 4. The method of claim 1, whereinpatterning the first metal layer in the predetermined shape comprises:coating a photoresist on the first metal layer; patterning thephotoresist in the predetermined shape; etching the first metal layerusing a patterned photoresist as a mask; and removing the patternedphotoresist.
 5. The method of claim 1, wherein, during etching of theglass substrate, the glass substrate is devoid of an organic materialthat has been disposed on the glass substrate.
 6. A method forfabricating a printing plate with a plurality of grooves, the methodcomprising: forming a first metal layer on a glass substrate including afirst region and a second region apart from the first region; patterningthe first metal layer in a predetermined shape to expose the glasssubstrate of the first region and the second region; dry etching theglass substrate of the first region and the second region to a firstdepth using a patterned first metal layer as a first etch mask; removingthe patterned first metal layer, thereby performing one cycle; forming asecond metal layer on the etched glass substrate; patterning the secondmetal layer to expose the glass substrate of the first region excludingthe second region; dry etching the etched glass substrate of the firstregion excluding the second region to a second depth using a patternedsecond metal layer as a second etch mask; wherein at least one ofgrooves having a wider width than that of the other grooves has deeperdepth that of the other grooves; wherein the first and second metallayers are etched when the glass substrate is etched, an etching rate ofthe first and the second metal layer is lower than the etching rate ofthe glass substrate and the etching ratio of the first and the secondmetal layer to the glass substrate is about 1:4 to about 1:10; andwherein a number of repetitions of the one cycle depends on a thicknessof the first metal layer and an etching depth of the glass substrate. 7.The method of claim 6, wherein the first depth of the second region isdifferent from the second depth of the first region.
 8. The method ofclaim 6, wherein the second depth is above 2 μm and the first depth isbelow 2 μm.